Mbthod op searchlight ventilation



' E. SP ERRY. METHOD OFSEARCHL IGHT VENTILATION.-

APPLICATION FILED APR. 3, 1916.

Patented 001114, 1919.

2 SHEETS-SHEET f' INVENTOR.

fZMER A5PRR Y A T70R25? E. A. SPERRY.

METHOD OF SEARCHLIGHT VENTILATION.

APPLICATKON FlLED-APR-S, I916.

,318,701; Patented 0ct.14,1919.

2 SHEETSSHEET 2- IN V E N TOR.

ELM 5? 147. 91 5719).

I My

A TTORN J,

. To all whom it may concern:

.nm rnnfsrArns PATENT OFFIC ELMER A. SPERRY, OI BROOKL YN, NEW YEJRK.

' un'rnon orsnancnmenr VENTILATION.

Specification ofLettcrs Patent.-

Patented Oct. 14, 1919..

Application filed April a. 1916. Serial no. as,49o.

Be it known that I, ELMER A. SPERRY, a citizen of the United States, residing at borough of Brooklyn, New York city, in the county of Kings and State :of' New York,

have invented Improved Methods of Searchlight Ventilation, of which the following is a specifi cation. This invention relates especially to searchlights employing flaming arc electrodes operated with heavy currents in which great heat and a large-quantity of fumes are produced. The heat produced is so intense as to crack the mirror and damage the drum and other parts of the Searchlight mechanism unless an eflicient cooling system is employed. Alsothe white 'fumes speedily condense onthe light concentrating device shown as a mirror, window and elsewhere and in a short time seriously impair the brillian'cy of the beam. The main objects of the invention are to dissipate this heat by cooling the drum, mirror, electrode holders, and other. parts and to force or draw out the fumes without causing flickering of the arc. The invention concerns especlally the type of Searchlight disclosed-in my co-pending applieation on improvements in searchllghts, Serial No. 21661, filed April 16th, 1915. Other objects of the invention are to im prove upon certain details of construction I of the lamp shown in said application.

Referring to the drawings, in which what I now consider to be the preferred form of my invention is shown Figure 1 is a vertical cross section of a Searchlight, the section being taken on line 11 of Fig. 2.

- Fig. 2 is a vertical longitudinal section of the same.

ing the mountin of the negative holder within the contro box.

Fig. 9 is a section of aportion of Fig. ,5 on line 99,Fig. 6. Fig. 10 is. a top View of a portion of Fig. 5. Fig.'11 shows a modification of the means for mounting the light concentrating devlce.

Fig. 12 is va detail of certain of the parts shown in Fig. 8.

As a'means for creating a circulation of air through the drum 1, I prefer to employ' a positive exhaust fan 2, driven by an elec trlc motor 3 and supported in a box 4 at the top of the drum and preferably above the are flame 5. The heated air and fumes drawn from the drum passout the openings 6,-7 as indicated by the arrows. Prior to entry into the drum, the air is caused to cool certain parts. The incoming air, or a portion thereof, is guided over the mirror 8preferably the back of the mirrorsothat theinirror will be cooled uniformly.

The problem of preventing Searchlight mirrors from cracking when an arc employing over 100 amperes is employed is much more perplexing than might appear from g a superficial inspection of the subject. I have found that merely cooling the mirror by a-current of air or otherwise as attempted by prior workers in. the art is worse, if anything, than no cooling at all, since unequal I cooling of the mirror surface will invariably crack it. By many experiments, in-,

volving the exploration of the mirror surface by means of thermal couples, I have determined'that by introducing the air adjacent the topof the mirror, which is the part receiving the most heat and causing it to flow downwardly over the mirror a substantially uniform" cooling is effected, since the coldest air is brought into contact with the hottest part of the mirror. By my invention the breakage of the mirrors is reduced almost to the vanishing point.

The air is introduced adjacentthe top of 10 and descends as indicated by the arrows to points 11, 12 near the bottom of the mirror, (Fig. 3) where it is led'into the ,drum

the mirror'through an opening 9 in shieldthrough baffle plates 13, 14 designed to deflect the air away from the arc to prevent its flaring and flickering. The lates also serve to cause the air to sweep the walls of the drum and to distribute the air currents throughout the length of the drum. The air escapes at 15 between plate 13 and the drum so that it is guidedover the inner surface of the drum. An additional baffle plate 16 may be providedif desired.

It will be noted that the air introduced into the drum, or the greater part thereof is warmed somewhat prior to entry into the drum, by passing down over the back of the InlI'IOI'. of cold air with the bottom or cooler portions of themirror. I

On account of the location of motor'3 at the top of the drum, I prefer to employ a ventilating systemtherefor to prevent overheating. The gases exhausted from the drum arenot well suited for this purpose,

being both hot and corrosive. Accordingly, I'prefer to utilize the outside air for this purpose and to shield the motor from the exhaust gases. I may provide a small fan 100 on the upper end of the motor shaft designed to draw air in through holes 101 and.

force it through the motor 3 and out open .-by means of rods 125.

ings 102, 103, as shown by arrows 130, or

simply the natural 'convectlon curren s may be utilized, in event the air would circulate in the opposite direction from that shown by the arrows 130.

In practice, I have found that the dull,

metallic drum becomes very much hotter than the bright mirror, which reflects. the heat and light rays, sothat'by interposing an artificially cooled member 17 between the drum 1 and mirror 8\ I am enabled to keep the mirror cool by preventing the heat of .the drum from being communicated to the m1rror.- Member 17 is. shown as a hollow ring having openings 18 to the air near the top thereof and being in communication with plates 13, l tnear the bottom, so that the air circulates down the ring as shown by arrows 19. Ring 17 also serves to shield the cllps 110 supporting the mirror from th direct radiation from the arc.

The lampportion of the Searchlight com-L prlses a positive electrode holder 20, and a negatlve electrode holder 21, through each of which the electrodes are fed automati-' cally. On account of the rapid consumption of the positive carbon in thistype of lamp, I find it necessary to employ a very long carbon 121, which v is allowed to project through an aperture 122 in the window 123. A tubular holder 124 may also be provided, which is secured to the front of the drum Both holders are cooled by an air blast or current and both holders serve to introduce current into their electrode.

By this means, I avoid the contact respective electrodes. Holder 20 is supported on a flattened tube 22 through which air is led into the holder. The body of the holder incloses at its rear feeding and rotating mechanism (not shown) and at its forward portion comprises cooling ribs 24:, around which is placed a shield 25 having a slot 26 near its top. Radial brushes 70 are employed to introduce the current into the The brushes are yieldingly pressed against the carbon by springs 71, 72 extending through the holder and secured adjacent each end to equalizing bars 73 extending across the brushes. On account of the intense heat near the arc and for the pur pose of preventing a too rapid conduction of meat away from the crater I attach a highly refractory sleeve 27 to the forward portion of the holder. The flaring end 28 of the sleeve is clamped at the forward end, preferably between shield 25 and the end of the holder, air-tight gaskets 127 being interposed therebetween. The ribs 24 are cut away at the bottoms so that the air coming in through tube 22 may circulate through all of the ribs. After assing up over the ribs, the

air emerges t rough slot 26 with considera sliding carriage 31 supported on a guideway 32 in box 126. Base 30 is provided with a central hollow extension 33 adapted to I lead air from tube 29 up to tube 28. The carriage 31 is moved on the guideway by means of the striking solenoid 34:, a bell crank lever 35 being swiveled adjacent one end to said carriage and at the'other end connected I to the core 36 of said solenoid.

Member 30 is made rotatable to facilitate the insertion of the negative carbon, when the lamp 'is within, the drum. A catch 37 may be provided to properly position the holder. On account of the small diameter of the negative carbon, andthe heavy currents employed, its resistance causes a con siderable loss of energy unless the current is introduced as close to the are as possible and in addition the electrode becomes heated, to a white heat causing oxidation and vap'orization back of the arc. The negative holder is designed with reference to this condition,.

by providing means to introduce current very close to the arc. v

The negative holder proper comprises a body portion in which airducts 39 are 46, so that when the rod is lifted the bracktween the brackets.

provided all' of which are in communic'a tion with tube 28. Hinged or flexible contact fingers 40'are secured to the forward portion of the body, the fingers being resiliently pressed into engagement .with the" electrode 41 by means of .flat springs 42. Fixed guides 43 are positioned betiveen the-- fingers, against which pins 44 on'thefingers.

are adapted-to bear when the carbon is withdrawn. The feed rollers 128. forthe" carbon.

are mounted on pivoted brackets 45', 46 and are held witha yielding pressure against the J carbon by means of spring '47 extending be? from feed shaft 48 by means ofgears 49 50,

5 1.and 51. In order to release the rollers,

when the holder 21 is turned around for insertion or release of a carbon,- I may provide a'rod 52 which engages a cam surface 53 on carriage 31" on rotation of the member 30 and is lifted thereby. Links 54 are 6011- nected at the top of the rod .to brackets 45,

et-s will be spread and the rollers released from the electrodes. The carbon may thenbef removed; or replaced through a slide or door 126 in the side of drum 1.

The air ducts 39 lead outfunder springs 42 and direct the air along the contact fingers 40. The size of the ducts ;is regulated to limit/the amount of air escaping so as to prevent the are from causing flickering of the air. The amountof air passed through the negative holder is small as compared to the amountholder. p s There are at least two reasons for employing'a comparatively rapid circulation ofair passed through the positive to cool the positive holder. One is that the positive electrode tip is heated to such ahigh temperature, that it is necessary to intensively pool the holder between the arc and the polnt where the current is led into the carbon through brushes 70, if the brushes are placed close to the arc. Another reason,

is that the heatedair in escaping from slot 26 with considerable Velocity entrains the fumes and vapors from the are and carries them directly to the exhaust fan 2; so that in contact with the mirror.

they are not allowed to fill the drum or come The'two motors 3 and 25 are preferably connected in parallel on the main circuit, and

are provided with separate starting switches 108,105 and regulating rheostats 108, 107,. an independent switch 104 and rheostat 106- being provided for the are, so that the-various parts may be operated independently.

I Fig; 11 shows a slightly modified form of mirror mounting in which the mirror 8, is-

supported-from the drum by means of clips 8', which are-preferably formed of resilient metal. -Heat insulating material '8 is interposed between the clips and the glass.

The rollers are' rotated results outlined, and the An artificially cooled ring 17 similar to ring 17 is alsoprovided, whichis designed so as to shield the cli ,8 from the direct radiation from the arc. ing 17 also aids in supporting the'clips s that they need not be in 0on tact-with the hot drum over a large surface, but are secured only tothe cooled ring. By

shielding the clips froYn the intense arc rays, addition, I am enabled to maintain the mirror support: at about the same temperature as the mirror,

When the operating current is swia'hdbn the arc will be struck by the rapid'retractiorf of the entire negative holder 21 as described,

and at thesame time the feeding mec anism for feeding the electrodes through the holders placed inoperation. At the same time the ventilatingand cooling means will be placed in full operation since said means are power driven and do not depend entirely upon convection currents for their {operation; The, blower 25' will :force air up through the hollow legs of the'electrodes and out of the top of the positive electrode. This i stream of a1r emerging to one side and directed toward the exhaust fan,3 entrains all of the fumes of the arc and carries them .directly'to the exhaust fan before'they come in contact with the mirror or drum. At the same. time, the 'air'drawn in through the bafiie plates 16 around the drum create-other currents of air directed toward the exhaust fan (see Fig. 1), but not in contact with the arc. The entire'drum is thus perfectly ventilated-and at the same timefdirect drafts on the are are avoided. By having the ventilating and cooling means positively driven and directed I also secure the ad-' vantage that the ventilating system will operate in any position of the Searchlight. This is of great advantagewhen the searchlight isnsedfor pickingup air craft since in siuch ajcase it 1s often desirable to place it. in a substantially vertical position.

In accordance with the provisions of the patent statutes, I have herein described the principle of operation of my invention, together with the apparatus, which I now consider .to' represent the best embodiment thereof, butI desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by 1. In a sear chlight, the combination with the light concentrating device and drinn, of

a fan connected therewith for causing a circulation of air through the drum and means for deflecting the incoming air awayv from the arc and around the walls of the drum.

2. In a searchlight, the combination with the light concentrating device and drum, of a fan connected therewith for causing a circulation of air through the drum, an inlet passage adapted to guide the air over the light concentrating device, and means for deflecting the incoming air around the interior walls of the drum to ventilate the interior of the Searchlight.

3. In a Searchlight, the combination with the light concentrating device and drum, of a fan connected therewith for causing a circulation of .air through the drum, an inlet passage adapted to guide the airdownwardly over the light concentrating device,

the lightconcentrating device and drum, of

a fan connected-therewith for causing acirculation of air through the drum, an inlet passage adapted to guide the air over the back of the light concentrating device, means for deflecting the incoming air around the walls of the drum, and means for introducing a current of air toward the said fan adjacent the electrode holders. v

6. In a flaming arc Searchlight, the combination with the light concentrating device and drum, of a fan connected therewith for causing a circulation of air through the drum, an inlet passage adapted to guide the air over the .backof the light concentrating device, means for deflecting the incoming air around the walls of the drum, and an air inlet adjacent an electrode holder.

7 The method of cooling Searchlight drums which consists in introducing air within,- around and adjacent the inner walls of the drum and also adjacent the central re gion of the drum.

8. In combination, a searchlight drum, baffle plates within, adjacent and approximately. concentric to the periphery of said A drum, said drum being provided with an opening permitting entry of air thereto and means for creating a draft in the space between saidba'flle plates and drum.

The method of cooling Searchlight which consists in introducing air within and adjacent the inner walls of the drum, in directing it circumferentially around the drum and in introducing a separate supply of air adjacent the central portion of the drum. 7

10. The method of cooling Searchlight drums which consists in introducing air within and adjacent the inner walls of the drum, in directing it circum'ferentially around the drum, in distributing it longitudinally of the drum and in introducing a separate supply of air adjacent the central portion of the drum.

11. A ventilating means for electric arc searchlights, comprising an exhaust or suction device adapted to exhaust the air from the drum and air blowing means for introducing air into the drum in a direction at a substantial angle to one of the electrodes.

12. A ventilating means for high intensity electric arc searchlights, comprising means for exhausting air from the drum and an air blowing means for introducing air into the druma'dj'acent to, but not in contact with the are.

13. A ventilating means for electric arc searchlights, comprising the combination with a drum, an exhaust fan adapted to draw air from said drum and means *i'tor introducing a draft of air adjacent to but directed away from the arc. v

14. In a searchlight, a drum, a pair of arc electrodes mounted within said drum, means for drawing air from said drum and-means for blowing air into said drum adjacent to the arc, and in a direction at a substantial angle to the electrodes.

15. In a searchlight, a drum, a pair of arc electrodes within said drum, means for exhausting air from said drum. and means for blowing air into said drum toward said first named means and away from the are.

16. In a Searchlight, a drum, a pair of arc electrodes,v means for exhausting air from said drum, means for blowing air into said drum anda passage for introducing the air from the last named means into said drum at a substantial angle to a line connecting the tips of the electrodes.

17 In a searchlight, a casing, an electrode holder within said casing, means for ex hausting air from said casing and means for introducing an air blast at a point within said casing on the side of. said electrode holder toward said first named means. I

18. In a Searchlight, a casing, an electrode holder mounted within said casing, means for exhausting air from said casing and means for blowing, air through said holder, said holder being provided with an opening on the side thereof which is toward said air exhausting means.

19. In a Searchlight, a drum, an exhaust opening therein, means for drawing air through said opening, means Ior producing an are within said drum, and means for causing and introducing a blast of air into said'drum at a place spaced from said opening but located a. shorter distance from said opening than the arc.

20. An electrode holder comprising a body portion provided with a central aperture for the electrode, and with cooling ducts, and axially extending spring' pressed fingers attached to said body, said ducts being adapted to cause a circulation of air along said fingers to cool the same.

' 21. In a searchlight, means for producing an are including an electrode holder, axially extending contact fingers on said holder for introducing current to the electrode close to the arc, ducts on said holder adapted to direct air along said fingers and means for causing air to pass through said ducts.

22. In a searchlight, an electrode holder,

axial fingers connected to said holder ada t- I ed to introduce current close to the active end of theelectrode, and means comprising air ducts on said holder for directing a cooling draft along said fingers.

23. In a searchlight, means including an electrode holder for producing an arc, axial fingers connected to said holder adapted to introduce current to the arc and means comprising air, ducts on said holder for directing a cooling draft along said fingers. L

24:. In a searchlight, an electrode holderlocated adjacent the arc, means for'feeding the electrode through the holder, a standard for supporting the electrode from adjacent the bottom of the drum, a slidably mounted base for the standard, and means for sliding the base to strike the arc.

25. In a searchlight, an electrode holder located adjacent the arc, means for feeding the electrode through the holder, a standard for supporting the electrode from adjacent the bottom of the drum, and means for moving the holder and standard toward and away from the are for striking the arc.

26. The combination with a searchlight drum, of an electrode holder located within the drum, a swivel mounting for the holder whereby the electrode may be turned toward the walls of the drum and a door in the drum \substantially opposite the electrode when so turned, whereby the electrode may be re-- v 28. In combination, a searchlight drum, an electrode'holder located within the drum,

feed rollers yieldingly mounted on the holder, a swivel mounting for the holder and means operated "by turning of the holder.

for spreading said rollers.

29. In combination, a Searchlight drum,

an electrode support located within the.

drum, means for gripping an electrode on said support, a swivel mounting for the support and means operated by turning the support for releasing said gripping means.

30. In combination, a searchlight drum, an electrode support located within the drum, means for grippingan electrode on 32. The combination with a searchlight,

having a reflector, of a back plate spaced from said reflector, an opening to the air adjacent the top of the reflector and means for drawing air in through said openin and downwardly over the back of said re ector to cool the same uniformly.

.33. The combination with a searchlight,

having a reflector and .adrum, of a back.

plate spaced from saidreflector, an opening to the air adjacent the top of the reflector, a v

passage leading from adjacent the bottom of the reflector, into the interior of the drum and means for drawing air in through said op ing downwardly over the back of said fi ctor and into said drum.

' 3-1. In a searchlight, the combination with the reflector and drum, of a fan connected therewith for causing a circulation of air through the drum, and an inlet passageway adapted to guide the air downwardly over the reflector, and into the drum;

35. Ina searchlight, the combination with a reflector and drum, of a fan connected therewith for causing a circulation of air through the drum, andan inlet passageway adapted to guide the air over the back of the reflector and into the drum.

36. In a searchlight, the combination with a drum and a reflector, of a member having a passage therethrough for'supporting the I device from the drum and means for circulating a cooling med1um therethrough.

37. In a searchlight, the combination with i I a'drum and a reflector, of a member having a passage therethrough for supporting the projector from the drum, a baffle plate ar'- ranged in rear of the reflector forminga' second passage and means for causing a circulation of air through both passages.

38. In a Searchlight, a metallic drum, a

.vitreous reflector, and an artificially cooled means for supporting the projector from the drum. I

. 39. In a Searchlight, the combination with a reflector, a drum and a source of light, a clip for supporting the mirror from the drum and a shield for the tween it and the said light, source. v

$0; In a searchlight, the combination with a reflector, a drum and a source of light, a clip for supporting themirror from the drum, a shield for the clip" located between it and the said light source and a positive means for cooling said shield.

41. In a Searchlight, the combination with clip located bea reflector, a drum and a source of light, a clip for supporting the mirror from the drum, an artificially cooled shield for the clip located between it and the said light 2 source, said clip being supported from the drum !by means of said shield.

42. In a searchli ht, the combination with a drum, a hollow e ectrode holder ositioned therein, a duct leading from without the 2 signature.

ELMER A. SPERRY. 

